1. Field of the Invention
The present invention is directed to circuitry for powering on or up of at least one powered down or off electronic component. In particular, the invention relates to a system employing at least one electronic component (e.g., processor) normally powered off but powered on in the presence of an RF communication signal. The system is designed to hold or maintain power to the component irrespective of interruption in RF communication of relatively short duration.
2. Description of Related Art
The use of a magnetically activated component such as transistors sensitive to magnetic fields, hall effect sensors, or Reed switches to non-invasively alter the characteristic, parameter, state, or program of an implantable medical device has been widely employed. In such application, an external magnet is placed proximate the magnetically activated component in the implantable medical device causing it to be programmed, altered or changed. International Publication WO9640366 is but one example of an apparatus and method for the control of an implantable device. The patented device employs a giant magnetoresistance ratio (GNR) sensor sensitive to external magnetic fields for programming the implantable medical device.
In order to conserve energy, it is desirable to power on specific electronic components, e.g., processors, only when necessary. This is particularly relevant in implantable medical devices powered by a limited power source, e.g., a battery, that requires surgery to be replaced. Those electronic components not required to be in continuous operation are normally maintained in a powered down or off state or mode. A component activated in the presence of a magnetic field may be employed to periodically power on the powered down electronic component when appropriate. The use of a magnetically activated component in medical applications, however, is circumspect. On the one hand the magnetic field must be sufficient in level to trigger the switch. On the other hand, exposure to a relatively large magnetic field may have a deleterious impact on the proper operation of the sensitive electronic circuitry of the medical device.
It is therefore desirable to solve the aforementioned problems by designing circuitry to detect the presence of an external RF communication signal and automatically power on at least one electronic component that is otherwise powered off without the use of a magnetically activated device.